Prismatic telescope, theater and field glass.



J.H.BARTON. PRISMATIG TELESCOPE, THEATER AND FIELD GLASS.

APPLIOATION FILED MAR. 14, 1911.

.1 0 16,315, I Patented Feb. 6, 191.2.v

CDLUMHIA PLANOGRAPH 60.. WfSHINUlON. u. c.

UNITED STATES rarnnr OFFICE.

JOHN HENRY BARTON, OF LONDON, ENGLAND.

PRISMATIC TELESCOPE, THEATER AND FIELD GLASS.

To all whom it may concern:

Be it known that I, JOHN HENRY BARTON, of 19 Honeywell road, WVandsworthCom mon, London, England, have invented certain new and usefulImprovements in Prismatic Telescopes, Theater and Field Glasses, ofwhich the following is a specification.

This invention relates to prismatic telescopes and prismatic theater andfield glasses comprising an erecting system consisting of two rightangle prisms disposed between the eyepiece and the objective and set inplanes at right angles with each other.

The object of the invention is to construct the same in such a mannerthat their thickness can be reduced to an extent which enables them tobe readily carried in an ordinary coat pocket, whereas with the ordinarymethod of construction the thickness is such that a case to contain theinstrument is practically a necessity.

The ordinary method of construction is to fix the two right angle prismsrigidly at right angles with each other. This method necessarily entailsthat the space occupied by the prisms is considerably greater than thethickness of either one of the prisms.

By means of this invention when the instrument is not in use the prismscan be made to occupy a space only slightly greater than the thicknessof one of them, so that the instrument can be made to assume a flat formvery convenient for carrying in the pocket.

Attempts have been made to construct prism field glasses and the like ofthis kind in a portable form, but these have mainly consisted inreducing the size of the prisms, and this necessitates a correspondingreduction in the size of the eyepieces, with a consequent loss of bothfield and light. With the present invention, however, large prisms andcorrespondingly large eyepieces can be used at the same time securingthe maximum portability.

According to the invention the two right angle prisms between theobjective and the eyepiece are disposed in separate cases rotatablyconnect-ed together so that one of them can be turned at an angle of 90relatively to the other into position at right angles thereto for use,and out of this position.

In carrying out my said invention I mount each prism in a separate metalcase, the said case consisting of the case proper and a coverSpecification of Letters Patent.

Application filed March 14, 1911.

Patented Feb. 6, 1912. Serial No. 614,384.

for closing the open end, and being just of sufficient widthconveniently to take the prism and allow of its adjustment. The caseshave apertures out in their ends to allow of the passage of the imagerays. Two of the said cases, together with an objective and eyepiece,telescope. The said two cases are connected together by a joint whichmay be formed on or in the apertures cut in their ends as aforesaid, andthey are kept in position by suitable means such as metal bars ofapproximately the same width as the prism cases themselves. One of thecases is rigidly fixed to one of the bars, but the other case is free torevolve through an arc of 90 on the joint aforesaid. It will be seenthat the two prisms thus mounted may either be placed in one and thesame plane or can be set at right angles with each other. On one of thesaid cases is affixed a tube for the purpose of carrying the objective,and on the other case a similar tube to carry the eyepiece. These tubesfor carrying the objective and eyepiece respectively are mounted overthe correspondin apertures in the ends of the cases. Suitabfe meansshould be provided for limiting the two end positions of the prisms.

Two of such prismatic telescopes as thus described may be mountedtogether to form form a complete prismatic a theater or field glass.This may be accomplished by means of the bars aforesaid which keep thecases in position. For this purpose the said bars may be extended andfitted together rigidly, or they may have a lateral sliding motion inorder to allow for difference in pupillary distance, but preferably theyhave joints formed on them in order that the pupillary distance may bevaried by a simple bending of the instrument. A suitable simultaneousfocusing mechanism can be fitted between the said joints, or theinstrument may be focused separately or independently. The focusing maybe effected either by moving the eyepiece or the objective.

The annexed drawings illustrate by way of example a binocular prismatictheater or field glass constructed in accordance with the invention.

Figure 1 is an elevation of the instrument partly in section, Fig. 2 isa plan.

For convenience the construction will be described with reference to oneside of the instrument, the other side being the counterpart. Each ofthe prisms 1, 2 is mounted in a separate metal case 3, 4 each of justsufiicient'width to take the prism conven-.

'case 4, and 12 is the cover for the open end of the top case 3. \Vhenthe instrument is constructed as a binocular the top cover 12 is madewith an extension to forni one half of the central joint. p

The prisms are held in positionin their cases by springs such as 7 andtheir horizontal faces are seated in loose shoes such as 8, formed withopenings 8 for the passage of the image rays. They can be adjusted inany known or suitable way.

The cases 3, 4 have apertures 9, 9 cut in their closed ends for thepassage of the image rays and are connected together by a joint formedby a shallowspigot 10 'of the aperture 9 in case 3 engaged in theaperture 9 of case 4 and seated on the shoulder formed by the peripheryof the aperture of case 4, a loose ring 11 being fitted on the spigotbetween the adjacent faces of the two cases. Any other suitable form ofjoint may be provided. The cases 3 and 4 are kept in position by reasonof the metal bar 12 (of approximately the same width as the prism case)being rigidly attached to the tube 13, which is itself rigidly attachedto one of the apertures cut in the endsof case 3. The prism case 3 isthus rigid with the bar 12 but the case 4 is free to revolve through anarc of 90 on the joint. A tube 13 carrying the objective, slides in thetubes 13 for the purpose of focusing, and a tube 15 carrying theeyepiece is screwed into the case 4, the apertures in the cases forthese tubes register with the corresponding apertures 83in the shoes 8.A ferrule 16 is screwed into a threaded hole 17 in the bar 12 andtightened up to clamp the case 4 rotatably in position. It will thus beseen that the two prism cases can thus be turned into one and the sameplane so as to lie flat,

or they can be turned into a position at right angles to each other foruse. V j

18 is a stop pin abutting against a shoulder 19 on the bar 12 andserving to limit the fiat position, and 20 is a flat spring formed witha hole to engage aprojection 21 on the case 3, in order to retain theprism cases in the right. angle position; by pressing on the springitcan be released for turning the prism cases. 7

The bars 12, 12 of the two counterpart arrangements of the binocularinstrument are shown as pivoted together in the known way so that theycan be turned on the central axis to adjust the pupillary distance.

In the drawings the prism cases on the left are shown in the fiatposition and those The instrument is also shown as provided with anordinary simultaneous focusing motion.

It will be understood that for single telescopes a single pair of prismcases mounted in the manner described will be employed.

What I claim and desire to secure by Letters Patent is 1. Prismatictelescopes, theater or field glasses, comprising in combination anobjective and an eyepiece, and an erecting system comprising a. pair ofright angle prisms, each of which is arranged to produce a doublereflection of a beam of light, said prisms being pivotally mounted withrespect to one another along an axis coincident with the path of a beamof light from one prism to the other.

2. Prismatic telescopes, theater or field glasses, comprising incombination an objective and an eyepiece, and an erect-ing systemcomprising a pair of right angle prisms, each of which is arranged toproduce a double reflection of a beam of light, a casing for each ofsaid prisms, said casings being pivot'ally mounted with respect to oneanother along an axis coincident with the path of a beam of light fromone prism to the other, and said eyepiece being mounted upon one of saidcasings and said objective upon the other.

3. Prismatic telescopes, theater or field glasses, comprising incombination a pair of objectives and a pair of eyepieces, and a pair oferecting systems each comprising a pair of right angle prisms, eachprism of each erecting system being arranged to produce a doublereflection of a beam of light, one of said objectives, eyepieces, anderecting systems being adjustable laterally with respect to the other.

4. Prismatic telescopes, theater or field glasses, comprising incombination a pair of objectives and a pair of eyepieces, and a pair oferecting systems each comprising a pair of right angle prisms, eachprism of each erect-ing system being arranged to produce a doublereflection of a beam of light, said prisms of each system beingpivotally mounted with respect to one another along an axis coincidentwith the path of a beam of light from one prism to the other, one ofsaid objectives, eyepieces, and erecting systems being adjustablelaterally with respect to the other.

5. Prismatic telescopes, theater or field glasses, comprising incombination an objective and an eyepiece, an erecting system consistingof two right angle prisms each of which is arranged to produce a doublereflection of a beam of'light, disposed between said objective andeyepiece, and separate cases rotatably connected together and whereinright angles to each other for use and out of this position forcarriage, substantially as described.

6. Prismatic telescopes, theater or field glasses, comprising incombination an objective and an eyepiece, an erecting system consistingof two right angle prisms each of which is arranged to produce adoublereflection of a beam of light, disposed between said objective andeyepiece, separate cases wherein said prisms are respectively mounted,apertures in said cases for the passage of the image rays and arotatable joint between said cases, whereby said prism cases can beturned into position at rightangles"for use and into position parallelto each other, substantially as described.

7. Prismatic telescopes, theater or field glasses, comprising incombination an objective and an eyepiece, an erecting system consistingof two right angle prisms each of which is arranged to produce a doublereflection of a beam of light, disposed be tween said objective andeyepiece, separate cases wherein said prisms are respectively mounted,said cases being rotatably connected together, whereby the prisms can beturned through a right angle in relation to each other, and means forsecuring the said cases in position at right angles to each other foruse, substantially as described.

8. Prismatic telescopes, theater or field glasses comprising incombination an objective and an eyepiece, an erecting system consistingof two right angle prisms each of which is arranged to produce a doublereflection of a beam of light, disposed be tween said objective andeyepiece, separate cases wherein said prisms are respectively mounted,said cases being rotatably connected together, whereby the prisms can beturned through a right angle in relation to each other, a spring catchfor securing said cases in position at right angles to each other foruse, and a stop for arresting the turning motion of the cases at theparallel position of the prisms, substantially as described.

9. A binocular telescope, theater or field glass, consisting of twoelements, each comprising an objective and an eyepiece, an erectingsystem consisting of two right angle prisms each of which is arranged toproduce a double reflection of a beam of light, disposed between saidobjective and eyepiece, separate cases wherein said prisms arerespectively mounted and which are rotatably connected together andadapted to be turned axially into position at right angles for use andinto position parallel to each other, means for securing said twoelements together and means for adjusting the pupillary distance,substantially as described.

10. A binocular telescope, theater or field glass, consisting of twoelements, each comprising an objective and an eyepiece, an erectingsystem consisting of two right angle prisms each of which is arranged toproduce a double reflection of a beainof light, disposed between saidobjective and eyepiece, separate cases wherein said prisms arerespectively mounted and which are rotatably connected together andadapted to be turned axially into position at right angles for use andinto position parallel to each other, an axial pivot to which said twoelements are connected and about which the same are rotatable foradjusting the pupillary dis tance, substantially as described.

11. Prismatic telescopes, theater or field glasses, comprising incombination an objective and an eyepiece, an erecting system consistingof two right angle prisms each of which is arranged to produce a doublereflection of a beam of light, disposed between said objective andeyepiece, separate cases wherein said prisms are respectively mounted, atube carrying said eyepiece and fixed to one of the cases and a tubecarrying said objective and fixed to the other case, and a rotatablejoint between said cases whereby the prisms can be turned into positionat right angles to each other for use and out of this position forcarriage.

12. Binocular telescopes, theater or field glasses, comprisingobjectives and eyepieces, said objectives being at a smaller distanceapart than said eyepieces, in combination with erecting systems disposedbetween the respective objectives and eyepieces and each comprising twosimple right angle prisms each of which is arranged to produce a doublereflection of a beam of light, separate cases wherein the right angleprisms of each erecting system are respectively mounted and which arerotatably connected together and adapted to be turned axially intoposition at right angles for use and into posit-ion parallel to eachother, substantially as described.

In witness whereof, I have hereunto signed my name in the presence oftwo subscribing witnesses.

JOHN HENRY BARTON.

l/Vitnesses GEORGE BELoE ELLIs, ROBERT MILTON SPEARPOINT.

Uopies of this patent may be obtained for five cents each, by addressingthe Commissioner of IPatents, Washington, D. G.

